This invention relates to a process for polymerizing polar a-olefinic monomers to "living" polymers and to the "living" polymers produced by such a process.
The technology known as group transfer polymerization is described in U.S. Pat. Nos. 4,417,034--Webster and 4,414,372--Farnham and Sogah, both granted in 1983, and in 4,508,880--Webster, granted Apr. 2, 1985. The former claims "living" polymers and their preparation from acrylic-type or maleimide monomers using defined organosilicon, -tin, or -germanium initiators and a catalyst which is a source of fluoride, cyanide or azide ions or a suitable Lewis acid. The latter is similar but uses as a co-catalyst a source of bifluoride ions. Both disclose various suitable solvents for the catalyst including acetonitrile used in amounts including 19 moles per mole of catalyst and more; acetonitrile is also used in even larger quantities as a general solvent for the polymerization.
By "living" polymer is meant a polymer of the invention which contains at least one active terminal group and is capable of polymerizing further in the presence of monomer(s) and co-catalyst. The words "living" and "livingness" are used herein in quotation marks to distinguish from any biological connotations.
In attempts to use group transfer polymerization to better advantage, it would be desirable to find ways to increase or enhance the duration of the "livingness" of the polymerization. This would involve somehow decreasing the proportion of termination to further polymerization events. This could lead to higher molecular weight, lower polydispersity, and better control and predictability of molecular weight.
Related applications include Ser. Nos. 660,588 abandoned and 660,589 U.S. Pat. No. 4,581,428 filed Oct. 18, 1984; 673,926 U.S. Pat. No. 4,681,918 filed Nov. 21, 1984; and 676,099 above filed Nov. 29, 1984. Also, U.S. Pat. No. 4,588,795--Dicker et al., granted May 13, 1986, discloses and claims the use of certain types of oxyanion catalysts in group transfer polymerization, and U.S. Pat. No. 4,622,372--Dicker et al., granted Nov. 11, 1986, discloses and claims livingness enhancement of such oxyanion catalyst using acetonitrile or silylated acetonitrile, but that may sometimes involve tying up some catalyst and thereby slowing down polymerization compared to the rate if all the catalyst were available.
The disclosures of the above-mentioned patents and applications are hereby incorporated by reference.